U.S. patent application number 13/290934 was filed with the patent office on 2012-03-01 for cutting sequence for net trimming a composite layup at an oblique angle.
This patent application is currently assigned to THE BOEING COMPANY. Invention is credited to Richard B. Evans, John Heigl.
Application Number | 20120048084 13/290934 |
Document ID | / |
Family ID | 39274019 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120048084 |
Kind Code |
A1 |
Evans; Richard B. ; et
al. |
March 1, 2012 |
Cutting Sequence for Net Trimming a Composite Layup at an Oblique
Angle
Abstract
To generate a bevel in an uncured composite layup, an edge of
part cut through the composite layup is performed at about
90.degree. relative to the composite layup and a bevel cut is
performed on the edge of part.
Inventors: |
Evans; Richard B.; (Maple
Valley, WA) ; Heigl; John; (Apache Jct., AZ) |
Assignee: |
THE BOEING COMPANY
Chicago
IL
|
Family ID: |
39274019 |
Appl. No.: |
13/290934 |
Filed: |
November 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12906449 |
Oct 18, 2010 |
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13290934 |
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11542225 |
Oct 4, 2006 |
7823490 |
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12906449 |
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Current U.S.
Class: |
83/39 |
Current CPC
Class: |
Y10T 83/0476 20150401;
B26D 7/086 20130101; Y10S 83/956 20130101; Y10T 83/04 20150401;
Y10T 83/8773 20150401; B26D 3/02 20130101; Y10T 83/0524
20150401 |
Class at
Publication: |
83/39 |
International
Class: |
B26D 3/02 20060101
B26D003/02 |
Claims
1. A method of generating a bevel cut, comprising: performing an
edge of part cut at an edge of part through an uncured composite
layup at about 90.degree. relative to the uncured composite layup,
wherein the uncured composite layup comprises a plurality of plies
of material laid in multiple directions, and wherein the plurality
of plies are pre-impregnated with a resin; and performing a bevel
cut proximal to the edge of part cut relative to the uncured
composite layup.
2. (canceled)
3. The method according to claim 1, further comprising: performing
the edge of part cut to penetrate through the uncured composite
layup to overcut into a supporting substrate.
4. The method according to claim 3, wherein the edge of part cut
penetrates about 0.05 inches (1.27 mm) into the supporting
substrate.
5-6. (canceled)
7. The method according to claim 1, wherein the uncured composite
layup includes up to 20 plies of composite material.
8. The method according to claim 1, wherein a single bevel blade is
utilized to perform the bevel cut.
9. The method according to claim 1, further comprising: performing
an intermediate cut prior to performing the bevel cut, the
intermediate cut penetrating an upper surface of the uncured
composite layup at about 90.degree. relative to the upper surface,
and wherein the intermediate cut is distal to the bevel cut and
also proximal to the edge of part cut, relative to the uncured
composite layup.
10. The method according to claim 9, further comprising: performing
the intermediate cut to a depth that essentially intersects the
bevel cut.
11. The method according to claim 9, wherein the intermediate cut
penetrates the upper surface of the uncured composite layup to a
depth of about 0.01 inches (0.25 mm) above the bevel cut.
12. The method according to claim 9, wherein the uncured composite
layup includes greater than 20 plies of composite material.
13. (canceled)
14. A method of cutting an uncured composite layup of up to 20
composite plies, the method comprising, cutting a periphery of an
uncured composite layup using an ultrasonic knife oriented
vertically relative to the uncured composite layup, the ultrasonic
knife being controlled to penetrate into a supporting substrate on
which the uncured composite layup is supported; and cutting a bevel
along the periphery using the ultrasonic knife, the ultrasonic
knife being controlled to cut away a scrap material without
penetrating the supporting substrate.
15. The method according to claim 14, further comprising:
controlling the ultrasonic knife to penetrate up to 0.05 inches
(1.27 rom) into the supporting substrate while cutting the
periphery.
16-18. (canceled)
19. The method according to claim 14, further comprising: cutting
an intermediate cut prior to cutting the bevel, the intermediate
cut being cut with the ultrasonic knife oriented vertically
relative to the uncured composite layup and the ultrasonic knife
penetrating an upper surface of the uncured composite layup to a
depth that cutting the bevel will essentially intersect, and
wherein the intermediate cut is between where the edge of part cut
intersects the upper surface of the uncured composite layup and the
bevel cut intersects the upper surface of the uncured composite
layup.
20. The method according to claim 19, wherein the ultrasonic knife
is controlled to penetrate the upper surface of the uncured
composite layup to a depth of about 0.01 inches (0.25 mm) above a
nominal bevel surface.
21. A method of cutting an uncured layup of more than 20 composite
plies, the method comprising, cutting a periphery of the uncured
layup using an ultrasonic knife oriented vertically, the ultrasonic
knife being controlled to penetrate below a supporting substrate on
which the uncured layup is supported; cutting an intermediate cut
into the uncured layup using the ultrasonic knife oriented
vertically, the intermediate cut being cut relatively inside the
periphery and at a predetermined depth above a nominal bevel
surface; and cutting a bevel on the uncured layup using the
ultrasonic knife, the bevel being cut in a plurality of passes, a
first pass of the plurality of passes comprising controlling the
ultrasonic knife to penetrate about to an intersection between the
nominal bevel surface and the periphery, a final pass of the
plurality of passes comprising controlling the bevel cutting
ultrasonic knife to sever a scrap material disposed relatively
above the nominal bevel surface and controlling the bevel cutting
ultrasonic knife to not penetrate the supporting substrate.
22. The method according to claim 21, further comprising:
controlling the ultrasonic knife to penetrate up to 0.05 inches
(1.27 mm) into the supporting substrate while cutting the
periphery.
23-25. (canceled)
26. The method according to claim 21, wherein the supporting
substrate includes an ultra high molecular weight polyethylene
polymer.
27. A method of generating a bevel in an uncured composite layup,
the method comprising: performing an edge of part cut at an edge of
part through the uncured composite layup at about ninety degrees
relative to the uncured composite layup; performing an intermediate
cut penetrating an upper surface of the composite layup at about
ninety degrees relative to the uncured composite layup, the
intermediate cut penetrating only partially through the uncured
composite layup, and the intermediate cut being proximal to the
edge of part cut relative to the uncured composite layup; and
performing a bevel cut in the uncured composite layup, the bevel
cut beginning at a location proximal to the intermediate cut,
relative to the uncured composite layup, and intersecting both the
intermediate cut and the edge of part cut.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to a device and
method of cutting composite material. More particularly, the
present invention pertains to a method of net trimming a layup of
composite ply material at an oblique angle and a device for doing
so.
BACKGROUND OF THE INVENTION
[0002] Composite structures are typically constructed from multiple
layers or plies. These plies may include a variety of materials
such as carbon fiber, various other fibers, metal foils, and the
like. In addition, the plies may be pre-impregnated with a resin
and are often dispensed from a roll or spool. Typically, multiple
plies are applied, one upon another, sometimes in multiple
directions, to generate a "layup" of the composite item. This layup
or "preform" is generally built up within a mold or over a form.
Often, the plies are slightly oversized to ease the layup process.
Depending upon the materials utilized and post-layup procedures
that may be performed, any excess composite material is cut from
the layup before or after the layup is cured.
[0003] Depending upon the particular application, it may be
preferable to remove any excess composite material before the layup
is cured. A disadvantage associated with conventional methods of
cutting uncured composite layup is that a cutting blade may adhere
to the layup and drag the composite material out of position. The
use of ultrasonic cutting blades reduces the tendency of the blade
to bind the resin, however, for relatively thick layups or when
cutting at an angle, conventional ultrasonic blades adhere to the
layup at an unacceptable rate.
[0004] Accordingly, it is desirable to provide a layup cutting
device and cutting method that is capable of overcoming the
disadvantages described herein at least to some extent.
SUMMARY OF THE INVENTION
[0005] The foregoing needs are met, to a great extent, by the
present invention, wherein in some embodiments a method of cutting
a bevel in an uncured composite layup is provided.
[0006] An embodiment of the present invention relates to a method
of generating a bevel in an uncured composite layup. In this
method, an edge of part cut through the composite layup is
performed at about 90.degree. relative to the composite layup and a
bevel cut is performed at the edge of part.
[0007] Another embodiment of the present invention pertains to a
method of cutting an uncured layup of up to 20 composite plies. In
this method, a periphery of the composite layup is cut using an
ultrasonic knife oriented vertically relative to the layup. The
ultrasonic knife is controlled to penetrate into a supporting
substrate on which the layup is supported. In addition, a bevel is
cut along the periphery using the ultrasonic knife. The bevel
cutting ultrasonic knife is controlled to cut away a scrap material
without penetrating the supporting substrate.
[0008] Yet another embodiment of the present invention relates to a
method of cutting an uncured layup of more than 20 composite plies.
In this method, a periphery of the layup is cut along using an
ultrasonic knife oriented vertically. The ultrasonic knife is
controlled to penetrate below a supporting substrate on which the
layup is supported. In addition, an intermediate cut is cut into
the layup using the ultrasonic knife oriented vertically. The
intermediate cut is cut relatively inside the periphery and at a
predetermined depth above a nominal bevel surface. Furthermore, a
bevel is cut on the layup using the ultrasonic knife. The bevel is
cut in a single pass controlling the bevel cutting ultrasonic knife
to sever a scrap material disposed relatively above the nominal
bevel surface and controlling the bevel cutting ultrasonic knife to
not penetrate the supporting substrate.
[0009] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0010] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0011] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is simplified view of a cutting system according to
an embodiment of the invention.
[0013] FIG. 2 is an cross-sectional view of the cutting system
during a first cut in a sequence of cuts performed according to an
embodiment of the invention.
[0014] FIG. 3 is an cross-sectional view of the cutting system
during a second cut in a sequence of cuts performed according to an
embodiment of the invention.
[0015] FIG. 4 is an cross-sectional view of the cutting system
illustrating a series of cut in a sequence of cuts performed
according to another embodiment of the invention.
[0016] FIG. 5 is a flow diagram for a method of cutting a layup
according to an embodiment of the invention.
DETAILED DESCRIPTION
[0017] The present invention provides, in an embodiment, a method
of net trimming or cutting a composite layup at an oblique angle.
The composite layup or preform cut by this method include, at
least, composite materials such as unidirectional tapes, fabrics,
foils, and/or films that have been pre-impregnated with a resin
"prepreg" and/or composite materials that have been otherwise bound
or tacked together. In this embodiment, a sequence of cuts is
performed that reduces drag upon a cutting blade. That is,
resistance and adherence of the layup to the blade is reduced. By
reducing drag, movement of the plies relative to other plies in the
layup is reduced and bending force or deflection of the blade is
reduced. In this manner, the sequence of cuts performed according
to an embodiment of the invention increases accuracy of the final
cut and minimizes disturbance of the layup, thereby, increasing
production, reducing production cost, and decreasing waste
associated with unacceptable movement of the layup during
cutting.
[0018] The invention will now be described with reference to the
drawing figures, in which like reference numerals refer to like
parts throughout. As shown in FIG. 1, a cutting system 10 includes
a tool 12, layup 14, stylus 16, ultrasonic transducer 18, and
positioning device 20. The tool 12 optionally provides a mold upon
which the layup 14 may be placed. In other embodiments, the layup
14 may be generated on a mold or mandrel and subsequently disposed
upon the tool 12 for cutting. The tool 12 provides a surface upon
which the layup 14 may be cut. In this regard, the tool 12 may
serve as an anvil and the tool 12 and the stylus 16 are juxtaposed
in co-operative alignment to facilitate cutting layup 14. That is,
the tool 12 provides supporting substrate for the layup 14 and
thereby facilitates the cutting action of the stylus 16.
[0019] The stylus 16 includes any suitable cutting, scoring, and
marking device. Depending upon the material to be cut and/or the
particular application, the ultrasonic transducer 18 is optionally
included to facilitate cutting the layup 14. For example, some
composite material utilized to fabricate the layup 14 may be
difficult to cut without vibrational energy supplied by the
ultrasonic transducer 18. When cutting such materials, the
ultrasonic transducer 18 is preferably included. When utilized, the
ultrasonic transducer 18 is configured to impart vibrational energy
upon the stylus 16. The stylus 16, when thusly energized, may
generate a crack front in the layup 14 that proceeds the stylus 16
and facilitates cutting.
[0020] The positioning device 20 moves or positions the stylus 16
relative to the layup 14. In various embodiments, the positioning
device 20 includes a head or stylus orientation assembly to rotate
the stylus 16 about one or more axes. The positioning device 20 may
also include a gantry, robotic armature, X-Y table, or the like to
move the stylus 16 relative to the layup 14. Movement of the stylus
16 relative to the layup 14 may be controlled in any suitable
manner.
[0021] An embodiment of the present invention pertains to a method
of cutting an uncured layup of up to about 20 composite plies. In a
specific example of this method, a periphery of the composite layup
is cut with the stylus 16 (e.g., an ultrasonic knife, or the like)
oriented vertically relative to the layup 14. The stylus 16 is
controlled to penetrate up to 0.05 inches (1.27 mm) into the tool
12 or other such supporting substrate on which the layup 14 is
supported. In addition, as shown in FIG. 3, a bevel is cut along
the periphery using the stylus 16 oriented at about 18.degree. to
about 21.degree. relative to the layup. The bevel cutting stylus 16
is controlled to cut away a scrap material without penetrating the
tool 12. FIG. 2 is an cross-sectional view of the cutting system 10
during a first cut in a sequence of cuts performed according to an
embodiment of the invention. As shown in FIG. 2, the stylus 16 is a
dual bevel blade. The stylus 16 is controlled to cut the layup 14
to an edge-of-part ("EOP") 30 that defines a final, outside or
periphery dimension, of a composite part or item. Accordingly, a
cut along the EOP 30 may be described as a periphery cut 32. To
fabricate the part, the layup 14 is typically generated with a
perimeter slightly beyond the EOP 30 and then cut along the EOP 30.
To facilitate cutting at the EOP 30, it may be preferable to
perform the periphery cut 32 with the stylus 16 oriented at
essentially 90.degree. to the layup 14. In this manner, the stylus
16 may cut through a relatively minimum amount of the layup 14. In
addition, as the incident angle of the cut deviates from
90.degree., deviations in the surface height of the tool 12 may
produce deviations from the EOP 30 of the cut. By performing the
periphery cut 32 at about 90.degree., this type of deviation may be
reduced.
[0022] According to an embodiment, while performing the periphery
cut 32 the stylus 16 is controlled to penetrate or cut slightly
below a bottom surface of the layup 14 to generate an overcut 34.
The overcut 34 facilitates separation of a scrap 36 from the layup
14. In general, the depth of the overcut 34 may be about 0.0 inch
(0.0 mm) to about 0.1 inches (2.54 mm). In a particular example,
the depth of the overcut 34 is about 0.05 inches (1.27 mm). In
another example, the actual depth of the overcut 34 is about 0.03
inches (0.76 mm) given a Z offset of about 0.02 inches (0.50 mm)
and setting for the 90.degree. cut of about 0.05 inches (1.27 mm).
To reduce wear or damage to the stylus 16, the tool 12 may include
a resilient material such as, for example, ultra high molecular
weight (UHMW) polyethylene polymers, Delrin.RTM., Vyon.RTM. nylon,
acetal; and the like. These and other materials may sustain many
hundreds or thousands of cuts without undue wear.
[0023] In some applications, one or more uncured parts are affixed
and co-cured to fabricate a unitary or one piece item. In a
particular example, the layup 14 includes a stringer that is a
component of an aircraft fuselage. To improve material properties
of the completed fuselage, the stringer and barrel are co-cured. To
increase an amount of contact area between the stringer and the
barrel, the EOP 30 of the layup 14 may be cut at a bevel 38.
[0024] Unfortunately, bevel cutting the EOP 30 has several
disadvantages. For example, as the cutting angle departs from
perpendicular (90.degree.), the length of a cutting edge of the
layup 14 in contact with the stylus 16 increases. As this cutting
edge length increases, resistance increases. The increased
resistance may result in stylus deflection, out of tolerance
trimming, layup movement, increased wear of the cutting system,
slower feed rates, and the like.
[0025] The stylus deflection may be exacerbated by bending forces
experienced by the stylus 16. In this regard, cutting at about
90.degree. tends to balance resistance encountered by each side of
the stylus 16 and thus, reduce torquing forces experienced by the
stylus 16. As the incident angle of the stylus 16 deviates from
90.degree., the torquing forces may increase. In addition, cuts
made into upper surface of the tool 12 at oblique angles may induce
premature degradation of the tool 12. This condition may be
exacerbated due to the incident angle of the stylus 14. That is, to
generate the overcut 34 at a predetermined depth, a greater length
of the stylus 16 will penetrate the tool 12 when the stylus 16 is
at an oblique angle. In a particular example, to generate the
overcut 34 at a depth of 0.05 inches (1.27 mm) and a stylus angle
of 22.degree., about 0.14 inches (-3.49 mm) of the stylus 16 may
cut into the tool 12. Furthermore, this oblique cut may generate a
flap in the surface of the tool 12 that may tend to raise an edge
and/or break off.
[0026] FIG. 3 is an axial view of the cutting system 10 during a
second cut in a sequence of cuts performed according to an
embodiment of the invention. As shown in FIG. 3, the stylus 16 is
controlled to perform a bevel cut 40 to cut the layup 14 at an
oblique angle. The bevel cut 40 generates the bevel 38 and a
relatively small scrap 42. The scrap 42 has relatively less mass
than the combined mass of the scrap 36 and the scrap 42 and
therefore provides relatively less resistance to the stylus 16. It
is an advantage of embodiments of the invention that ramp or bevel
cuts may be performed in uncured composite layups at less than
21.degree. to about 18.degree.. It is another advantage that these
bevel cuts may be performed in layups with greater than 20
composite plies
[0027] Preferably, the stylus 16 is controlled to essentially cut
at or slightly above an intersection of the EOP 30 and the tool 12
and substantially on or parallel to the bevel 38. If the stylus 16
cuts relatively below the intersection of the EOP 30 and the tool
12, a loss in continuity of the EOP 30 may result as the bevel cut
may proceed relatively to the inside of the EOP 30. To avoid
potential loss in continuity of the EOP 30, the stylus 16 may be
controlled to cut relatively above the intersection of the EOP 30
and the tool 12. In a particular example, the stylus 16 may be
controlled to cut about 0.01 inches (0.25 mm) above the
intersection of the EOP 30 and the tool 12. In another example, the
stylus 16 may be controlled to cut essentially at the intersection
of the EOP 30 and the tool 12. In actual practice, given a Z offset
above the tool 12 of 0.02 inches (0.50 mm) and assuming an
approximate downward blade deflection of 0.0005 inches (0.13 mm),
the tip of the stylus 16 may, in fact, be about 0.015 inches (0.37
mm) above the surface of the tool 12.
[0028] As shown in FIG. 3, the stylus 16 utilized to generate the
bevel 38 optionally includes a single bevel edge profile. The
single bevel edge profile, if utilized, may facilitate cutting the
bevel 38. It is an advantage of embodiments of the invention, that
by first cutting the EOP 30 in an essentially perpendicular stylus
orientation (as shown in FIG. 2) and then generating the bevel 38
(as shown in FIG. 3), the EOP 30 is more precisely cut. It is
another advantage that wear on the stylus 16 is reduced. It is yet
another advantage that wear on the tool 12 is reduced.
[0029] As shown in FIG. 3, the bevel 38 and corresponding bevel cut
40 are at an angle of about 18.degree. relative to the tool 12.
However, in other examples, the bevel 38 and corresponding bevel
cut 40 need not be at 18.degree., but rather, may be at any
suitable angle. Suitable bevel angles include, at least,
16.degree., 19.degree., 22.degree. or greater with the surface of
the tool 12, and the like,
[0030] An embodiment of the present invention relates to a method
of cutting a relatively thick uncured layup of more than about 20
composite plies. In a specific example of this method, a periphery
of the layup 14 is cut with the stylus 16 oriented vertically. The
stylus 16 is controlled to penetrate up to 0.05 inches below the
tool 12 or other such supporting substrate on which the layup 14 is
supported. In addition, as shown in FIG. 4, one or more
intermediate cuts are cut into the layup using the stylus 16
oriented vertically. These intermediate cuts are cut relatively
inside the periphery and at a predetermined depth above a nominal
bevel surface. Furthermore, as shown in FIG. 3, a bevel is cut on
the layup 14 using the stylus 16 oriented at 18 to 21 degrees
relative to tool 12. In a particular example, the bevel is cut in a
single pass controlling the stylus 16 to penetrate about to an
intersection between the nominal bevel surface and the periphery to
sever a scrap material disposed relatively above the nominal bevel
surface and controlling the bevel cutting stylus 16 to not
penetrate the tool 12. FIG. 4 is an cross-sectional view of the
cutting system 10 making a series of perpendicular cuts in a
sequence of cuts performed according to another embodiment of the
invention. As shown in FIG. 4. the series of perpendicular cuts
include one or more intermediate cuts 50 and the periphery cut 32.
Depending upon a variety of factors, the intermediate cuts 50 may
improve cutting performance. These factors may include, for
example, layup thickness, composite material properties, bevel 38
angle, empirical results, and the like. For example, when bevel
cutting a relatively thick layup 24 at a relatively shallow bevel
38, the scrap 42 cut from the layup 14 may resist release or
removal. Examples of relatively shallow bevel 38 angles include
angles of about 14.degree. to about 18.degree. relative to the
surface of the tool 12. The intermediate cuts 50 subdivide the
scrap 42 into a plurality of scrap 42a to 42n. Due to the reduction
in cross-sectional area, each of the scrap 42a to 42n has less
rigidity and offers less resistance to release than the undivided
scrap 42.
[0031] In the particular example shown, two intermediate cuts 50a
and 50b are shown. However, any suitable number of intermediate
cuts 50a to 50n are included in embodiments of the invention. To
perform the intermediate cuts 50a and 50b, the stylus 16 is
controlled to cut at or just above the bevel 38 (e.g., a nominal
bevel surface). Cutting slightly above the nominal bevel surface
reduces the likelihood that the intermediate cuts 50a to 50n may
score the nominal bevel surface. In a particular example, the
stylus 16 is controlled to cut about 0.01 inches (0.25 mm) above
the nominal bevel surface. To perform the periphery cut 32, the
stylus 16 is controlled to cut essentially at the EOP 30.
Preferably, the stylus 16 is further controlled to generate the
overcut 34.
[0032] In various embodiments, the perpendicular cuts may be
performed in any suitable order. For example, the periphery cut 32
may be performed first, followed be intermediate cut 50b, then 50a.
Alternatively, intermediate cut 50a may be performed first,
followed by 50b, and then followed by the periphery cut 32. In
addition, some or all of the cuts 50a, 50b, and 32 may be performed
at essentially the same time.
[0033] To generate the bevel 38, the stylus 16 may be controlled to
perform the bevel cut 40 as shown in HG. 3. In a particular
example, following the series of perpendicular cuts shown in FIG.
4, the bevel cut 40 may be performed. In another example, the bevel
cut 40 may be performed in a series of steps. More specifically,
during or following the intermediate cut 50a, a bevel cut 40a may
cut along a portion of the bevel 38 up to or slightly beyond the
intermediate cut 50a. Similarly, additional bevel cuts may be
performed to correspond to intermediate cuts 50b to 50n. The height
of a final bevel cut performed to correspond to the periphery cut
32 is controlled to be at or slightly above the tool 12 to avoid
damage to the tool 12 and/or cutting inside of the EOP 30.
[0034] FIG. 5 is a flow diagram for a method 60 of cutting a layup
according to an embodiment of the invention. Prior to initiation of
the method 60, a variety of preparative operations may be
performed. For example, a composite item may be designed, a layup
corresponding to the item may be generated, the cutting system 10
may be powered, the stylus 16 may be oriented, and the like. In
addition, depending upon the cutting operation, a stylus may be
selected and installed in the cutting system 10. In a particular
example, to perform vertical cuts, a symmetric or dual bevel knife
may be selected. In another example, to perform the bevel cut, a
single bevel knife may be selected. The selected knife may be
optimized to cut while being excited by an ultrasonic transducer 18
or horn. In yet another example, a rotary knife may be selected to
perform one or more cutting operations.
[0035] At step 62, it is determined whether one or more of the
intermediate cuts 50a to 50n is to be performed. For example, if
the layup 14 is relatively thick, the bevel relatively shallow,
and/or the composite materials relatively difficult to cut, it may
be determined that one or more intermediate cuts 50a to 50n may be
performed at step 64. If it is determined that the intermediate
cuts 50a to 50n may be omitted, the periphery cut 32 may be
performed at step 66.
[0036] At step 64, the one or more intermediate cuts 50a to 50n may
be performed. For example, as shown in FIG. 4, the stylus 16 is
controlled to cut at or just above the bevel 38 (e.g., a nominal
bevel surface). In various embodiments, the intermediate cuts 50a
to 50n may be performed before, during or after the periphery cut
32.
[0037] At step 66, the periphery cut 32 may be performed. For
example, as shown in FIG. 2, the stylus 16 is controlled to cut the
layup 14 essentially along the periphery or EOP 30 of the layup
14.
[0038] At step 68, the bevel cut 40 may be performed. For example,
the positioning device 20 is controlled to position the stylus 16
to cut along the bevel 38. In various embodiments, the bevel cut 40
may be performed as a single cut that generates the bevel 38 or as
two or more bevel cuts 40a to 40n that may be performed along with
or alternating with the step 64 and/or step 66. The bevel cut 40
may be performed at any suitable angle. Suitable angles include,
for example, about 15.degree. to about 85.degree. relative to an
upper surface of the layup 14. More particularly, the bevel cut is
performed at about 16.degree. to about 25.degree. relative to an
upper surface of the layup 14. More particularly yet, the bevel cut
is performed at about 18.degree. to about 21.degree. relative to an
upper surface of the layup 14.
[0039] At step 70, the scrap 36, 42, and/or 42a to 42n may be
removed. For example, the scrap 36, 42, and/or 42a to 42n may be
blown, drawn, or swept away. In various embodiments, the scrap may
be removed as it is generated or at the completion of the cuts.
Following the step 70, the cutting system 10 may idle or stop until
another cutting operation is performed.
[0040] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
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